Les auteurs tiennent à remercier Cui Chao, étage de Kort, Stoop Esther et Ralph Carvalho pour les images de la figure 4, Ulrike Nehrdich et Davy de Witt pour les soins de poissons, et les membres de laboratoire pour d&#39;autres discussions utiles. Ce travail est soutenu par le Programme Smart Mix du ministère néerlandais des affaires économiques et le ministère de l&#39;Education, la Culture et de la Science, de la 7ème Commission européenne cadre du projet ZF-Santé (Santé-F4-2010-242048), l&#39;Union européenne Marie-Curie Formation initiale réseau FishForPharma (PITN-GA-2011-289209), et par le NHMRC australien (637 394). L&#39;Australien de médecine régénérative Institut est soutenu par des subventions du gouvernement de l&#39;État de Victoria et le gouvernement australien.

<ol>
	<li>Meijer, A. H., Spaink, H. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Host-pathogen+interactions+made+transparent+with+the+zebrafish+model.">Host-pathogen interactions made transparent with the zebrafish model.</a> Curr. Drug Targets. 12, 1000-1017 (2011).</li><li>Davis, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Real-time+visualization+of+mycobacterium-macrophage+interactions+leading+to+initiation+of+granuloma+formation+in+zebrafish+embryos.">Real-time visualization of mycobacterium-macrophage interactions leading to initiation of granuloma formation in zebrafish embryos.</a> Immunity. 17, 693-702 (2002).</li><li>vander Sar, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+embryos+as+a+model+host+for+the+real+time+analysis+of+Salmonella+typhimurium+infections.">Zebrafish embryos as a model host for the real time analysis of Salmonella typhimurium infections.</a> Cell Microbiol. 5, 601-611 (2003).</li><li>Zakrzewska, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophage-specific+gene+functions+in+Spi1-directed+innate+immunity.">Macrophage-specific gene functions in Spi1-directed innate immunity.</a> Blood. 116, 1-11 (2010).</li><li>Le Guyader, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Origins+and+unconventional+behavior+of+neutrophils+in+developing+zebrafish.">Origins and unconventional behavior of neutrophils in developing zebrafish.</a> Blood. 111, 132-141 (2008).</li><li>Herbomel, P., Thisse, B., Thisse, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ontogeny+and+behaviour+of+early+macrophages+in+the+zebrafish+embryo.">Ontogeny and behaviour of early macrophages in the zebrafish embryo.</a> Development. 126, 3735-3745 (1999).</li><li>Alibaud, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Mycobacterium+marinum+TesA+mutant+defective+for+major+cell+wall-associated+lipids+is+highly+attenuated+in+Dictyostelium+discoideum+and+zebrafish+embryos.">A Mycobacterium marinum TesA mutant defective for major cell wall-associated lipids is highly attenuated in Dictyostelium discoideum and zebrafish embryos.</a> Mol. Microbiol. 80, 919-934 (2011).</li><li>Carvalho, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+high-throughput+screen+for+tuberculosis+progression.">A high-throughput screen for tuberculosis progression.</a> PLoS One. 6, 16779-16779 (2011).</li><li>van der Sar, A. M., Spaink, H. P., Zakrzewska, A., Bitter, W., Meijer, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Specificity+of+the+zebrafish+host+transcriptome+response+to+acute+and+chronic+mycobacterial+infection+and+the+role+of+innate+and+adaptive+immune+components.">Specificity of the zebrafish host transcriptome response to acute and chronic mycobacterial infection and the role of innate and adaptive immune components.</a> Mol. Immunol. 46, 2317-2332 (2009).</li><li>Rosen, J. N., Sweeney, M. F., Mably, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microinjection+of+Zebrafish+Embryos+to+Analyze+Gene+Function.">Microinjection of Zebrafish Embryos to Analyze Gene Function.</a> J. Vis. Exp. (25), e1115-e1115 (2009).</li><li>Kimmel, C. B., Ballard, W. W., Kimmel, S. R., Ullmann, B., Schilling, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stages+of+embryonic+development+of+the+zebrafish.">Stages of embryonic development of the zebrafish.</a> Dev. Dyn. 203, 253-310 (1995).</li><li>Westerfield, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Zebrafish+Book.">The Zebrafish Book.</a> A Guide for the Laboratory Use of Zebrafish (Brachydanio rerio). , (1993).</li><li>Gutzman, J. H., Sive, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+Brain+Ventricle+Injection.">Zebrafish Brain Ventricle Injection.</a> J. Vis. Exp. (26), e1218-e1218 (2009).</li><li>Ellett, F., Pase, L., Hayman, J. W., Andrianopoulos, A., Lieschke, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=mpeg1+promoter+transgenes+direct+macrophage-lineage+expression+in+zebrafish.">mpeg1 promoter transgenes direct macrophage-lineage expression in zebrafish.</a> Blood. 117, 49-56 (2011).</li><li>Stockhammer, O. W., Zakrzewska, A., Hegedus, Z., Spaink, H. P., Meijer, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcriptome+profiling+and+functional+analyses+of+the+zebrafish+embryonic+innate+immune+response+to+Salmonella+infection.">Transcriptome profiling and functional analyses of the zebrafish embryonic innate immune response to Salmonella infection.</a> J. Immunol. 182, 5641-5653 (2009).</li><li>Renshaw, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+transgenic+zebrafish+model+of+neutrophilic+inflammation.">A transgenic zebrafish model of neutrophilic inflammation.</a> Blood. 108, 3976-3978 (2006).</li><li>Stoop, E. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+embryo+screen+for+mycobacterial+genes+involved+in+the+initiation+of+granuloma+formation+reveals+a+newly+identified+ESX-1+component.">Zebrafish embryo screen for mycobacterial genes involved in the initiation of granuloma formation reveals a newly identified ESX-1 component.</a> Dis. Model Mech. 4, 526-536 (2011).</li><li>Levraud, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+the+zebrafish+IFN+receptor:+implications+for+the+origin+of+the+vertebrate+IFN+system.">Identification of the zebrafish IFN receptor: implications for the origin of the vertebrate IFN system.</a> Journal of Immunology. 178, 4385-4394 (2007).</li><li>Levraud, J. P., Colucci-Guyon, E., Redd, M. J., Lutfalla, G., Herbomel, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+analysis+of+zebrafish+innate+immunity.">In vivo analysis of zebrafish innate immunity.</a> Methods Mol. Biol. 415, 337-363 (2008).</li><li>Brothers, K. M., Newman, Z. R., Wheeler, R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Live+imaging+of+disseminated+candidiasis+in+zebrafish+reveals+role+of+phagocyte+oxidase+in+limiting+filamentous+growth.">Live imaging of disseminated candidiasis in zebrafish reveals role of phagocyte oxidase in limiting filamentous growth.</a> Eukaryot. Cell. 10, 932-944 (2011).</li><li>Colucci-Guyon, E., Tinevez, J. Y., Renshaw, S. A., Herbomel, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+of+professional+phagocytes+in+vivo:+unlike+macrophages,+neutrophils+engulf+only+surface-associated+microbes.">Strategies of professional phagocytes in vivo: unlike macrophages, neutrophils engulf only surface-associated microbes.</a> J. Cell Sci. 124, 3053-3059 (2011).</li><li>van Soest, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+static+immersion+and+intravenous+injection+systems+for+exposure+of+zebrafish+embryos+to+the+natural+pathogen+Edwardsiella+tarda.">Comparison of static immersion and intravenous injection systems for exposure of zebrafish embryos to the natural pathogen Edwardsiella tarda.</a> BMC Immunology. 12, 58-58 (2011).</li><li>Adams, K. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drug+tolerance+in+replicating+mycobacteria+mediated+by+a+macrophage-induced+efflux+mechanism.">Drug tolerance in replicating mycobacteria mediated by a macrophage-induced efflux mechanism.</a> Cell. 145, 39-53 (2011).</li><li>Ellett, F. L., Lieschke, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Computational+quantification+of+fluorescent+leukocyte+numbers+in+zebrafish+embryos.">Computational quantification of fluorescent leukocyte numbers in zebrafish embryos.</a> Methods in Enzymology. , (2011).</li><li>Yuan, S., Sun, Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microinjection+of+mRNA+and+Morpholino+Antisense+Oligonucleotides+in+Zebrafish+Embryos.">Microinjection of mRNA and Morpholino Antisense Oligonucleotides in Zebrafish Embryos.</a> J. Vis. Exp. (27), e1113-e1113 (2009).</li><li>Mathias, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resolution+of+inflammation+by+retrograde+chemotaxis+of+neutrophils+in+transgenic+zebrafish.">Resolution of inflammation by retrograde chemotaxis of neutrophils in transgenic zebrafish.</a> J. Leukoc. Biol. 80, 1281-1288 (2006).</li><li>Hall, C., Flores, M. V., Storm, T., Crosier, K., Crosier, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+zebrafish+lysozyme+C+promoter+drives+myeloid-specific+expression+in+transgenic+fish.">The zebrafish lysozyme C promoter drives myeloid-specific expression in transgenic fish.</a> BMC Dev. Biol. 7, 42-42 (2007).</li><li>Gray, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+intravital+imaging+of+macrophage+and+neutrophil+behaviour+during+inflammation+using+a+novel+transgenic+zebrafish.">Simultaneous intravital imaging of macrophage and neutrophil behaviour during inflammation using a novel transgenic zebrafish.</a> Thromb. Haemost. 105, 811-819 (2011).</li></ol>

Les auteurs n&#39;ont rien à révéler.

Les méthodes d&#39;infection décrites dans cet article sont fréquemment utilisés pour étudier la fonction de gènes de l&#39;hôte de l&#39;immunité innée ou des gènes de virulence bactériens 1. Les micro-injection par voie intraveineuse (méthodes des protocoles 5 et 6.1) sont utilisés le plus souvent pour de telles études. La veine caudale à l&#39;île du sang postérieure est l&#39;endroit le plus commode pour l&#39;injection intraveineuse de 1-jour vieux embryons. Comme la veine caudale devient plus difficile de pénétrer à des stades ultérieurs, nous préférons le canal de Cuvier en tant que site d&#39;injection par voie intraveineuse pour les embryons à 2-3 dpf. Dans tous les cas, il est essentiel d&#39;injecter des embryons avec des chiffres cohérents de bactéries, ce qui doit être vérifiée par l&#39;injection de placage inoculums pour le comptage des CFU. Les aspects suivants doivent être considérés pour atteindre injections reproductibles. Tout d&#39;abord, il est essentiel de disposer d&#39;aiguilles de haute qualité en verre injection microcapillaires. Si la pointe de l&#39;aiguille est trop grande, l&#39;injection va créer un trou de perforation assez grand pour des saignements de se produire etles bactéries injectées s&#39;écoule de la circulation sanguine. Deuxièmement, les bactéries doivent être injectés directement dans la circulation sanguine. Si la pointe de l&#39;aiguille n&#39;est pas à l&#39;intérieur de la veine ou si les écarts de fluides d&#39;injection dans l&#39;extension du sac vitellin, l&#39;embryon doit être mis au rebut de l&#39;expérience. Troisièmement, à l&#39;aide PVP40 comme support pour injecter M. marinum aidera à prévenir les bactéries de sombrer dans l&#39;aiguille de verre. PVP40 améliore l&#39;homogénéité de la suspension, ce qui entraîne inoculums plus reproductibles pendant toute la durée d&#39;injections. PVP40 peut également être utilisé pour S. injections typhimurium, mais ici il est moins important parce que la plus grande taille et de la fluorescence lumineuse des bactéries permet un contrôle visuel sur l&#39;inoculum d&#39;injection au cours des expériences. Pour pratiquer les injections, nous recommandons l&#39;utilisation de phénol colorant rouge (1% v / v) ou 1 pm sphères fluorescentes disponibles en différentes couleurs (Invitrogen). Une fois que la technique est maîtrisée, il faut environ 30 minutes pour injecter 50-100 embryons, y compris le temps nécessaire pour aligner les embryons sur des plaques d&#39;agarose et le réglage du volume d&#39;injection bactérienne. Alors que les injections intraveineuses dans l&#39;île du sang (protocole 5) ou dans le canal de Cuvier (protocole 6.1) sont les plus couramment utilisés, les autres voies d&#39;infection décrites dans cet article la vidéo se sont révélées utiles pour étudier des macrophages et des neutrophiles chimiotactisme (protocoles 6.2, 6.3 , et 6.4), pour étudier la croissance des souches bactériennes atténuées (protocole 6.5), et d&#39;adapter le modèle d&#39;infection le poisson-zèbre pour applications à haut débit (protocole 6.6) 4-8. Les décrits de micro-injection méthodes peuvent également être appliquées pour des injections de virus 18, 19, les spores fongiques 14, 20 ou parasites protozoaires (Maria Forlenza, communication personnelle). Un complément utile aux procédures d&#39;injection décrites dans cet article la vidéo est une procédure récemment décrit pour injection sous-cutanée de bactéries dans zebrembryons afish 21. Cette procédure a été appliquée à l&#39;étude la phagocytose des bactéries par les neutrophiles, qui ont été trouvés pour les bactéries de manière efficace sur les surfaces des tissus engloutissent, mais, contrairement à macrophages, étaient pratiquement incapables de phagocyter les bactéries lors de l&#39;injection dans le sang ou dans les cavités corporelles remplies de liquide. Pour les embryons injections sous-cutanées sont positionnés les mêmes que pour les injections musculaires queue décrites dans cet article la vidéo, mais l&#39;aiguille est insérée sous la peau pour injecter des bactéries sur une somite. Il est important de considérer que la micro-injection est essentiellement une voie artificielle de l&#39;infection. Cependant, les embryons précoces sont très résistants à l&#39;exposition externe aux pathogènes bactériens. En fait, les essais d&#39;immersion, où les embryons sont baignés dans une suspension bactérienne, ne sont pas reproductibles dans nos mains 22. Alors que certains embryons peuvent être infectés lors de l&#39;immersion, nous avons observé une grande variation dans les taux de mortalité et de l&#39;expressions de gènes marqueurs inflammatoires entre les embryons individuels dans de tels essais. Les méthodes d&#39;injection de micro-décrites dans cet article d&#39;atteindre les infections reproductibles et sont particulièrement utiles pour étudier les interactions bactéries avec les cellules immunitaires innées d&#39;accueil. Une approche efficace pour quantifier une infection bactérienne chez les embryons individuels est d&#39;analyser les images fluorescentes d&#39;embryons infectés par le sur-mesure, le logiciel dédié pixel quantification 17, 23. Cette approche a été démontré une bonne corrélation avec les résultats de UFC après placage d&#39;embryons infectés. De même, les changements relatifs dans le nombre de leucocytes par embryon ont été quantifiés par analyse d&#39;image numérique dans les lignes de leucocytes transgéniques journaliste fluorophores; cette approche serait applicable à la quantification de la réponse de l&#39;hôte à l&#39;infection leukopoietic 24. La fonction de gènes immunitaires innées de l&#39;hôte peuvent être étudiés efficacement in vivo par la combinaison des modèles d&#39;infection décritesavec effet de choc morpholino. Morpholinos sont des oligonucléotides antisens synthétiques qui ciblent ARN spécifiques et de réduire l&#39;expression des produits géniques lorsqu&#39;il est injecté dans 1-cellules embryons de poisson zèbre scène comme le montre la vidéo d&#39;autres articles dans cette revue 10, 25. Dans les études knockdown morpholino, il est d&#39;une grande importance que tous les groupes d&#39;embryons doivent être comparées sont mis en scène correctement avant les injections bactériennes. Ceci est particulièrement important parce que les embryons ont un système immunitaire en développement qui devient de plus en plus compétente au fil du temps. Il ya plusieurs lignes de reporter transgéniques actuellement disponibles pour distinguer les grands sous-ensembles innées immunitaire, les macrophages et les polynucléaires neutrophiles, en embryons de poisson zèbre. Le megapixels et promoteurs Lyz ont été utilisés pour générer des lignes de reporter neutrophiles 16, 26, 27, et le CSF1R (FMS) et MPEG1 promoteurs ont été utilisés pour produire des journalistes macrophages 14, 28. Alors que csf1r (FMS) est en outre exprimé dans xanthophores, mpeg1 expression est exclusivement dans les macrophages. Comme le montre dans cet article la vidéo, les mpeg1 récemment mis au point des lignes journaliste sont très utiles pour la phagocytose par les macrophages imagerie bactérienne.

<table border="1"><tbody><tr><td> Réactif </td><td> Fournisseur </td><td> Numéro de catalogue </td></tr><tr><td> Rouge de phénol </td><td> Sigma </td><td> P0290 </td></tr><tr><td> Glycérol </td><td> Sigma-Aldrich </td><td> 228210 </td></tr><tr><td> Difco agar Middlebrook 7H10 </td><td> Becton, Dickinson and Company </td><td> 262710 </td></tr><tr><td> BBL Middlebrook OADC enrichissement </td><td> Becton, Dickinson and Company </td><td> 211886 </td></tr><tr><td> Difco Bouillon Middlebrook 7H9 </td><td> Becton, Dickinson and Company </td><td> 271310 </td></tr><tr><td> BBL Middlebrook ADC enrichissement </td><td> Becton, Dickinson and Company </td><td> 211887 </td></tr><tr><td> Tween 80 </td><td> Sigma-Aldrich </td><td> P1754 </td></tr><tr><td> Polyvinylpyrrolidone (PVP40) </td><td> Calbiochem, Merck KGaA </td><td> 529504 </td></tr><tr><td> N &lt;/ Em&gt;-phénylthiourée (PTU) </td><td> Sigma-Aldrich </td><td> P7629 </td></tr><tr><td> Ethyl 3-aminobenzoate sel de méthanesulfonate (tricaïne) </td><td> Sigma-Aldrich </td><td> A5040 </td></tr><tr><td> Méthylcellulose </td><td> Sigma-Aldrich </td><td> M0387 </td></tr><tr><td> SeaPlaque agarose (agarose à faible point de fusion) </td><td> Lonza Inc </td><td> 50100 </td></tr><tr><td> FluoSpheres (1,0 um, rouge fluorescent (580/605)) </td><td> Invitrogen </td><td> F8821 </td></tr><tr><td> FluoSpheres (1,0 um, jaune-vert fluorescent (505/515)) </td><td> Invitrogen </td><td> F8823 </td></tr></tbody></table>

infection of zebrafish embryos with intracellular bacterial pathogens

Poisson zèbre (Danio rerio) embryons sont de plus en plus utilisé comme un modèle pour étudier la fonction du système immunitaire des vertébrés innée dans les interactions hôte-pathogène 1. Les principaux types de cellules du système immunitaire inné, les macrophages et les neutrophiles, les développer au cours des premiers jours de l&#39;embryogenèse avant la maturation des lymphocytes qui sont nécessaires pour les réponses immunitaires adaptatives. La facilité d&#39;obtention de grands nombres d&#39;embryons, leur accessibilité en raison du développement externe, la transparence optique de stades embryonnaire et larvaire, un large éventail d&#39;outils génétiques, de vastes ressources mutantes et des collections de lignes de reporter transgéniques, tous les ajouter à la polyvalence du poisson-zèbre modèle. Salmonella enterica sérotype Typhimurium (S. typhimurium) et Mycobacterium marinum peut résider intracellulaire dans les macrophages et sont fréquemment utilisés pour étudier les interactions hôte-pathogène chez les embryons de poisson zèbre. Les processus d&#39;infection de ces deuxdes bactéries pathogènes sont intéressants à comparer car S. infection aiguë et typhimurium est mortelle dans la journée, tandis que M. l&#39;infection marinum est chronique et peut être imagée en place au stade larvaire 2, 3. Le site de micro-injection de bactéries dans l&#39;embryon (Figure 1) détermine si l&#39;infection deviendra rapidement systémique ou un premier temps restent localisées. Une infection systémique rapide peut être établie par micro-injection des bactéries directement dans la circulation sanguine via la veine caudale à l&#39;île du sang postérieure ou via le canal de Cuvier, un canal large diffusion sur le sac vitellin reliant le cœur de la vascularisation du tronc. Au 1 dpf, lorsque les embryons à ce stade ont macrophages phagocytically actifs, mais les neutrophiles n&#39;ont pas encore mûri, l&#39;injection dans l&#39;île du sang est préférable. Pour les injections à 2-3 dpf, lorsque les embryons ont également développé fonctionnels (myéloperoxydase-productrice) neutrophiles, le canal de Cuvier est préférable que tsite d&#39;injection, il. Pour étudier la migration dirigée des cellules myéloïdes vers les infections locales, les bactéries peuvent être injectés dans le muscle queue, vésicule otique, ou rhombencéphale ventricule 4-6. En outre, la notochorde, une structure qui semble être normalement inaccessibles aux cellules myéloïdes, est très sensible à l&#39;infection locale 7. Une alternative utile pour applications à haut débit est l&#39;injection de bactéries dans le jaune d&#39;embryons dans les premières heures après la fécondation 8. La combinaison de bactéries fluorescentes et les lignes de poisson-zèbre transgénique avec des macrophages ou de neutrophiles fluorescentes crée des conditions idéales pour l&#39;imagerie multi-couleur des interactions hôte-pathogène. Cet article décrira vidéo des protocoles détaillés pour l&#39;infection par voie intraveineuse et locale des embryons de poisson zèbre avec S. typhimurium ou M. bactéries marinum et pour l&#39;imagerie de fluorescence ultérieure de l&#39;interaction avec les cellules du système immunitaire inné.

Watch this Scientific Journal Video about Infection of Zebrafish Embryos with Intracellular Bacterial Pathogens at JoVE.com

Infection of Zebrafish Embryos with Intracellular Bacterial Pathogens

Embryons de poisson zèbre transparent ont prouvé hôtes modèle utile pour visualiser et les interactions entre l&#39;étude fonctionnellement les cellules immunitaires innées et bactéries pathogènes intracellulaires, tels que<em&gt; Salmonella typhimurium</em&gt; Et<em&gt; Mycobacterium marinum</em&gt;. Micro-injection de bactéries et de multi-couleur d&#39;imagerie de fluorescence sont des techniques essentielles intervenant dans l&#39;application de poisson-zèbre modèles d&#39;infection d&#39;embryons.

L&#39;infection des embryons de poisson zèbre avec bactéries pathogènes intracellulaires

Zebrafish (Danio rerio) embryos are increasingly used as a model for studying the function of the vertebrate innate immune system in host-pathogen ...

infection-of-zebrafish-embryos-with-intracellular-bacterial-pathogens

Research

JoVE Journal

Immunology and Infection

43.5K vues.  Leiden University. Embryons de poisson zèbre transparent ont prouvé hôtes modèle utile pour visualiser et les interactions entre l'étude fonctionnellement les cellules immunitaires innées et bactéries pathogènes intracellulaires, tels que Salmonella typhimurium Et Mycobacterium marinum. Micro-injection de bactéries et de multi-couleur d'imagerie de fluorescence sont des techniques essentielles intervenant dans l'application de poisson-zèbr...

Vidéo: Infection of Zebrafish Embryos with Intracellular Bacterial Pathogens

'Bioluminescent' Reporter Phage for the Detection of Category A Bacterial Pathogens

Yersinia pestis and Bacillus anthracis are Category A bacterial pathogens that are the causative agents of the plague and anthrax, respectively 1. Although the natural occurrence of both diseases&#39; is now relatively rare, the possibility of terrorist groups using these pathogens as a bioweapon is real. Because of the disease&#39;s inherent communicability, rapid clinical course, and high mortality rate, it is critical that an outbreak be detected quickly. Therefore methodologies that provide rapid detection and diagnosis are essential to ensure immediate implementation of public health measures and activation of crisis management.
Recombinant reporter phage may provide a rapid and specific approach for the detection of Y. pestis and B. anthracis. The Centers for Disease Control and Prevention currently use the classical phage lysis assays for the confirmed identification of these bacterial pathogens 2-4. These assays take advantage of naturally occurring phage which are specific and lytic for their bacterial hosts. After overnight growth of the cultivated bacterium in the presence of the specific phage, the formation of plaques (bacterial lysis) provides a positive identification of the bacterial target. Although these assays are robust, they suffer from three shortcomings: 1) they are laboratory based; 2) they require bacterial isolation and cultivation from the suspected sample, and 3) they take 24-36 h to complete. To address these issues, recombinant &#34;light-tagged&#34; reporter phage were genetically engineered by integrating the Vibrio harveyi luxAB genes into the genome of Y. pestis and B. anthracis specific phage 5-8. The resulting luxAB reporter phage were able to detect their specific target by rapidly (within minutes) and sensitively conferring a bioluminescent phenotype to recipient cells. Importantly, detection was obtained either with cultivated recipient cells or with mock-infected clinical specimens 7.
For demonstration purposes, here we describe the method for the phage-mediated detection of a known Y. pestis isolate using a luxAB reporter phage constructed from the CDC plague diagnostic phage &#934;A1122 6,7 (Figure 1). A similar method, with minor modifications (e.g. change in growth temperature and media), may be used for the detection of B. anthracis isolates using the B. anthracis reporter phage W&#946;::luxAB 8. The method describes the phage-mediated transduction of a biolumescent phenotype to cultivated Y. pestis cells which are subsequently measured using a microplate luminometer. The major advantages of this method over the traditional phage lysis assays is the ease of use, the rapid results, and the ability to test multiple samples simultaneously in a 96-well microtiter plate format.
<img alt="Figure 1" src="/files/ftp_upload/2740/2740fig1.jpg" /> 
Figure 1. Detection schematic. The phage are mixed with the sample, the phage infects the cell, luxAB are expressed, and the cell bioluminesces. Sample processing is not necessary; the phage and cells are mixed and subsequently measured for light.

&#039;Bioluminescent&#039; Reporter Phage for the Detection of Category A Bacterial Pathogens

A simple method for the identification of priority bacterial pathogens is to use genetically engineered reporter phage. These reporter phage, which are specific to their particular host species, are capable of rapidly transducing a bioluminescent signal response to host cells. Herein, we describe the use of reporter phage for the detection of Yersinia pestis.

Phage »Bioluminescent&quot; Reporter pour la détection des bactéries pathogènes de la catégorie A

Yersinia pestis and Bacillus anthracis are Category A bacterial pathogens that are the causative agents of the plague and anthrax, respectively 1. ...

Recherche

Immunologie et infection

Single Cell Measurements of Vacuolar Rupture Caused by Intracellular Pathogens

Shigella flexneri are pathogenic bacteria that invade host cells entering into an endocytic vacuole. Subsequently, the rupture of this membrane-enclosed compartment allows bacteria to move within the cytosol, proliferate and further invade neighboring cells. Mycobacterium tuberculosis is phagocytosed by immune cells, and has recently been shown to rupture phagosomal membrane in macrophages. We developed a robust assay for tracking phagosomal membrane disruption after host cell entry of Shigella flexneri or Mycobacterium tuberculosis. The approach makes use of CCF4, a FRET reporter sensitive to &beta;-lactamase that equilibrates in the cytosol of host cells. Upon invasion of host cells by bacterial pathogens, the probe remains intact as long as the bacteria reside in membrane-enclosed compartments. After disruption of the vacuole, &beta;-lactamase activity on the surface of the intracellular pathogen cleaves CCF4 instantly leading to a loss of FRET signal and switching its emission spectrum. This robust ratiometric assay yields accurate information about the timing of vacuolar rupture induced by the invading bacteria, and it can be coupled to automated microscopy and image processing by specialized algorithms for the detection of the emission signals of the FRET donor and acceptor. Further, it allows investigating the dynamics of vacuolar disruption elicited by intracellular bacteria in real time in single cells. Finally, it is perfectly suited for high-throughput analysis with a spatio-temporal resolution exceeding previous methods. Here, we provide the experimental details of exemplary protocols for the CCF4 vacuolar rupture assay on HeLa cells and THP-1 macrophages for time-lapse experiments or end points experiments using Shigella flexneri as well as multiple mycobacterial strains such as Mycobacterium marinum, Mycobacterium bovis, and Mycobacterium tuberculosis.

We describe a method for tracking the endomembrane rupture elicited by the intracellular bacteria Shigella flexneri and Mycobacterium tuberculosis upon host cell invasion. Our assay makes use of CCF4, a host cytoplasmic FRET probe in live or fixed cells. This reporter is degraded by an enzyme activity present on the bacterial surface.

Simples mesures de cellules de rupture Vacuolar causées par des pathogènes intracellulaires

Shigella flexneri are pathogenic bacteria that invade host cells entering into an endocytic vacuole. Subsequently, the rupture of this membrane-enclosed ...

Discovery of New Intracellular Pathogens by Amoebal Coculture and Amoebal Enrichment Approaches

Intracellular pathogens such as legionella, mycobacteria and Chlamydia-like organisms are difficult to isolate because they often grow poorly or not at all on selective media that are usually used to cultivate bacteria. For this reason, many of these pathogens were discovered only recently or following important outbreaks. These pathogens are often associated with amoebae, which serve as host-cell and allow the survival and growth of the bacteria. We intend here to provide a demonstration of two techniques that allow isolation and characterization of intracellular pathogens present in clinical or environmental samples: the amoebal coculture and the amoebal enrichment. Amoebal coculture allows recovery of intracellular bacteria by inoculating the investigated sample onto an amoebal lawn that can be infected and lysed by the intracellular bacteria present in the sample. Amoebal enrichment allows recovery of amoebae present in a clinical or environmental sample. This can lead to discovery of new amoebal species but also of new intracellular bacteria growing specifically in these amoebae. Together, these two techniques help to discover new intracellular bacteria able to grow in amoebae. Because of their ability to infect amoebae and resist phagocytosis, these intracellular bacteria might also escape phagocytosis by macrophages and thus, be pathogenic for higher eukaryotes.

Amoebal coculture is a cell culture system using adherent amoebae to selectively grow intracellular pathogens able to resist phagocytic cells such as amoebae and macrophages. It thus represents a key tool to discover new infectious agents. Amoebal enrichment allows discovery of new amoebal species and of their specific intracellular bacteria.

Découverte de nouveaux agents pathogènes intracellulaires par amibienne Coculture et approches amibienne enrichissement

Intracellular pathogens such as legionella, mycobacteria and Chlamydia-like organisms are difficult to isolate because they often grow poorly or not at ...

Generation and Multi-phenotypic High-content Screening of Coxiella burnetii Transposon Mutants

Invasion and colonization of host cells by bacterial pathogens depend on the activity of a large number of prokaryotic proteins, defined as virulence factors, which can subvert and manipulate key host functions. The study of host/pathogen interactions is therefore extremely important to understand bacterial infections and develop alternative strategies to counter infectious diseases. This approach however, requires the development of new high-throughput assays for the unbiased, automated identification and characterization of bacterial virulence determinants. Here, we describe a method for the generation of a GFP-tagged mutant library by transposon mutagenesis and the development of high-content screening approaches for the simultaneous identification of multiple transposon-associated phenotypes. Our working model is the intracellular bacterial pathogen Coxiellaburnetii, the etiological agent of the zoonosis Q fever, which is associated with severe outbreaks with a consequent health and economic burden. The obligate intracellular nature of this pathogen has, until recently, severely hampered the identification of bacterial factors involved in host pathogen interactions, making of Coxiella the ideal model for the implementation of high-throughput/high-content approaches.

Generation and Multi-phenotypic High-content Screening of Coxiella burnetii Transposon Mutants

Coxiella burnetii is an obligate intracellular Gram-negative bacterium responsible for the zoonotic disease Q fever. Here we describe methods for the generation of Coxiella fluorescent transposon mutants as well as the automated identification and analysis of the resulting internalization, replication and cytotoxic phenotypes.

Génération et multi-phénotypique criblage à haut contenu de<em&gt; Coxiella burnetii</em&gt; Mutants de transposon

Invasion and colonization of host cells by bacterial pathogens depend on the activity of a large number of prokaryotic proteins, defined as virulence ...

Applying an Inducible Expression System to Study Interference of Bacterial Virulence Factors with Intracellular Signaling

The technique presented here allows one to analyze at which step a target protein, or alternatively a small molecule, interacts with the components of a signaling pathway. The method is based, on the one hand, on the inducible expression of a specific protein to initiate a signaling event at a defined and predetermined step in the selected signaling cascade. Concomitant expression, on the other hand, of the gene of interest then allows the investigator to evaluate if the activity of the expressed target protein is located upstream or downstream of the initiated signaling event, depending on the readout of the signaling pathway that is obtained. Here, the apoptotic cascade was selected as a defined signaling pathway to demonstrate protocol functionality. Pathogenic bacteria, such as Coxiella burnetii, translocate effector proteins that interfere with host cell death induction in the host cell to ensure bacterial survival in the cell and to promote their dissemination in the organism. The C. burnetii effector protein CaeB effectively inhibits host cell death after induction of apoptosis with UV-light or with staurosporine. To narrow down at which step CaeB interferes with the propagation of the apoptotic signal, selected proteins with well-characterized pro-apoptotic activity were expressed transiently in a doxycycline-inducible manner. If CaeB acts upstream of these proteins, apoptosis will proceed unhindered. If CaeB acts downstream, cell death will be inhibited. The test proteins selected were Bax, which acts at the level of the mitochondria, and caspase 3, which is the major executioner protease. CaeB interferes with cell death induced by Bax expression, but not by caspase 3 expression. CaeB, thus, interacts with the apoptotic cascade between these two proteins.

The method described here is used to induce the apoptotic signaling cascade at defined steps in order to dissect the activity of an anti-apoptotic bacterial effector protein. This method can also be used for inducible expression of pro-apoptotic or toxic proteins, or for dissecting interference with other signaling pathways.

L&#39;application d&#39;un système d&#39;expression inductible pour étudier les interférences de facteurs de virulence bactérienne avec signalisation intracellulaire

The technique presented here allows one to analyze at which step a target protein, or alternatively a small molecule, interacts with the components of a ...

Identification of Rare Bacterial Pathogens by 16S rRNA Gene Sequencing and MALDI-TOF MS

There are a number of rare and, therefore, insufficiently described bacterial pathogens which are reported to cause severe infections especially in immunocompromised patients. In most cases only few data, mostly published as case reports, are available which investigate the role of such pathogens as an infectious agent. Therefore, in order to clarify the pathogenic character of such microorganisms, it is necessary to conduct epidemiologic studies which include large numbers of these bacteria. The methods used in such a surveillance study have to meet the following criteria: the identification of the strains has to be accurate according to the valid nomenclature, they should be easy to handle (robustness), economical in routine diagnostics and they have to generate comparable results among different laboratories. Generally, there are three strategies for identifying bacterial strains in a routine setting: 1) phenotypic identification characterizing the biochemical and metabolic properties of the bacteria, 2) molecular techniques such as 16S rRNA gene sequencing and 3) mass spectrometry as a novel proteome based approach. Since mass spectrometry and molecular approaches are the most promising tools for identifying a large variety of bacterial species, these two methods are described. Advances, limitations and potential problems when using these techniques are discussed.

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and molecular techniques (16S rRNA gene sequencing) permit the identification of rare bacterial pathogens in routine diagnostics. The goal of this protocol lies in the combination of both techniques which leads to more accurate and reliable data.

Identification des bactéries pathogènes rares par 16S ARNr Gene Séquençage et MALDI-TOF MS

There are a number of rare and, therefore, insufficiently described bacterial pathogens which are reported to cause severe infections especially in ...

Isolation of Single Intracellular Bacterial Communities Generated from a Murine Model of Urinary Tract Infection for Downstream Single-cell Analysis

In this article, we outline a procedure used to isolate individual intracellular bacterial communities from a mouse that has been experimentally infected in the urinary tract. The protocol can be broadly divided into three sections: the infection, bladder epithelial cell harvesting, and mouth micropipetting to isolate individual infected epithelial cells. The isolated epithelial cell contains viable bacterial cells and is nearly free of contaminating extracellular bacteria, making it ideal for downstream single-cell analysis. The time taken from the start of infection to obtaining a single intracellular bacterial community is about 8 h. This protocol is inexpensive to deploy and uses widely available materials, and we anticipate that it can also be utilized in other infection models to isolate single infected cells from cell mixtures even if those infected cells are rare. However, due to a potential risk in mouth micropipetting, this procedure is not recommended for highly infectious agents.

This protocol describes a simple method of isolating single, infected-bladder epithelial cells from a murine model of urinary tract infection.

Isolement des simples communautés bactériennes intracellulaires généré à partir d’un modèle murin d’Infection des voies urinaires pour l’analyse de cellules individuelles en aval

In this article, we outline a procedure used to isolate individual intracellular bacterial communities from a mouse that has been experimentally infected ...

Opsonophagocytic Killing Assay to Assess Immunological Responses Against Bacterial Pathogens

A key aspect of the immune response to bacterial colonization of the host is phagocytosis. An opsonophagocytic killing assay (OPKA) is an experimental procedure in which phagocytic cells are co-cultured with bacterial units. The immune cells will phagocytose and kill the bacterial cultures in a complement-dependent manner. The efficiency of the immune-mediated cell killing is dependent on a number of factors and can be used to determine how different bacterial cultures compare with regard to resistance to cell death. In this way, the efficacy of potential immune-based therapeutics can be assessed against specific bacterial strains and/or serotypes. In this protocol, we describe a simplified OPKA that utilizes basic culture conditions and cell counting to determine bacterial cell viability after co-culture with treatment conditions and HL-60 immune cells. This method has been successfully utilized with a number of different pneumococcal serotypes, capsular and acapsular strains, and other bacterial species. The advantages of this OPKA protocol are its simplicity, versatility (as this assay is not limited to antibody treatments as opsonins), and minimization of time and reagents to assess basic experimental groups.

This opsonophagocytic killing assay is used to compare the ability of phagocytic immune cells to respond to and kill bacteria based on different treatments and/or conditions. Classically, this assay serves as the gold&#160;standard for assessing effector functions of antibodies raised against a bacterium as opsonin.

Opsonophagocytic meurtre dosage pour évaluer les réponses immunologiques contre les bactéries pathogènes

A key aspect of the immune response to bacterial colonization of the host is phagocytosis. An opsonophagocytic killing assay (OPKA) is an experimental ...

Visualization of Macrophage Lytic Cell Death During Mycobacterial Infection in Zebrafish Embryos via Intravital Microscopy

Zebrafish is an excellent model organism for studying innate immune cell behavior due to its transparent nature and reliance solely on its innate immune system during early development. The Zebrafish Mycobacterium marinum (M. marinum) infection model has been well-established in studying host immune response against mycobacterial infection. It has been suggested that different macrophage cell death types will lead to the diverse outcomes of mycobacterial infection. Here we describe a protocol using intravital microscopy to observe macrophage cell death in zebrafish embryos following M. marinum infection. Zebrafish transgenic lines that specifically label macrophages and neutrophils are infected via intramuscular microinjection of fluorescently labeled M. marinum in either the midbrain or the trunk. Infected zebrafish embryos are subsequently mounted on low melting agarose and observed by confocal microscopy in X-Y-Z-T dimensions. Because long-term live imaging requires using low laser power to avoid photobleaching and phototoxicity, a strongly expressing transgenic is highly recommended. This protocol facilitates the visualization of the dynamic processes in vivo, including immune cell migration, host pathogen interaction, and cell death.

This protocol describes a technique for visualizing macrophage behavior and death in embryonic zebrafish during Mycobacterium marinum infection. Steps for the preparation of bacteria, infection of the embryos, and intravital microscopy are included. This technique may be applied to the observation of cellular behavior and death in similar scenarios involving infection or sterile inflammation.

Visualisation de la mort des cellules lytiques de Macrophage pendant l'infection mycobactérienne dans les embryons de poisson zèbre par l'intermédiaire de la microscopie intravitale

Zebrafish is an excellent model organism for studying innate immune cell behavior due to its transparent nature and reliance solely on its innate immune ...

Determination of Chemical Inhibitor Efficiency against Intracellular Toxoplasma Gondii Growth Using a Luciferase-Based Growth Assay

Toxoplasma gondii is a protozoan pathogen that widely affects the human population. The current antibiotics used for treating clinical toxoplasmosis are limited. In addition, they exhibit adverse side effects in certain groups of people. Therefore, discovery of novel therapeutics for clinical toxoplasmosis is imperative. The first step of novel antibiotic development is to identify chemical compounds showing high efficacy in inhibition of parasite growth using a high throughput screening strategy. As an obligate intracellular pathogen, Toxoplasma can only replicate within host cells, which prohibits the use of optical absorbance measurements as a quick indicator of growth. Presented here is a detailed protocol for a luciferase-based growth assay. As an example, this method is used to calculate the doubling time of wild-type Toxoplasma parasites and measure the efficacy of morpholinurea-leucyl-homophenyl-vinyl sulfone phenyl (LHVS, a cysteine protease-targeting compound) regarding inhibition of parasite intracellular growth. Also described, is a CRISPR-Cas9-based gene deletion protocol in Toxoplasma using 50 bp homologous regions for homology-dependent recombination (HDR). By quantifying the inhibition efficacies of LHVS in wild-type and TgCPL (Toxoplasma cathepsin L-like protease)-deficient parasites, it is shown that LHVS inhibits wild-type parasite growth more efficiently than &#916;cpl growth, suggesting that TgCPL is a target that LHVS binds to in Toxoplasma. The high sensitivity and easy operation of this luciferase-based growth assay make it suitable for monitoring Toxoplasma proliferation and evaluating drug efficacy in a high throughput manner.

Determination of Chemical Inhibitor Efficiency against Intracellular Toxoplasma Gondii Growth Using a Luciferase-Based Growth Assay

Presented here is a protocol to evaluate the inhibition efficacy of chemical compounds against in vitro intracellular growth of Toxoplasma gondii using a luciferase-based growth assay. The technique is used to confirm inhibition specificity by genetic deletion of the corresponding target gene. The inhibition of LHVS against TgCPL protease is evaluated as an example.

Détermination de l’efficacité de l’inhibiteur chimique contre la croissance intracellulaire de Toxoplasma Gondii utilisant un essai de croissance basé sur luciferase

Toxoplasma gondii is a protozoan pathogen that widely affects the human population. The current antibiotics used for treating clinical toxoplasmosis are ...